I recently put in a new IAC and i cleaned with carburetor cleaner and when i pull the wiring connector off of the IAC and the truck doesnt try to stall or die or anything. All the time if in Park or Nuetral the idle is 1600, but when in gear its at 1200ish. it never was like this before i put the new IAC in. the IAC was used, does this mean its bad? before when i pulled the connector off with my old IAC it died immediately, does that mean it was still good? im most worried about the idle. can it damage my truck? any an all advice is welcome!!!

 

It's hard on everything. If you unplug it and no effect on idle, it's not working (if the wires & connector is intact). I'd try another one, or put the old one that was working back on & run Error code scans afterwards. The Valves seldom fail. Their Solenoid component however does!